First, the big picture. These two charts show the time period from 1900 to 2010. On top, the bars show the total deaths per year per 100,000 people. The bottom shows our average life-expectancy, which continues to increase. And now on to what kills us...

The biggest cause of death today is heart disease. Heart disease has been the leading cause of death for most of the past century. Interestingly, though, the heart disease "epidemic" peaked in the 1960s at about 350 deaths per 100,000 people. It has since been cut in half.